1. Field of the Invention
The invention relates to machines for the preparation of cards with embossed alphanumeric text and one or more tracks of magnetically recorded digitally encoded information. Cards of the aforementioned type are known conventionally as credit cards.
2. Description of the Prior Art
The assignee of the present invention has marketed an embossing system with the model identification of the Model 1803. That embossing system is characterized by a high throughput of embossed cards, is smaller in size than its predecessors used for embossing cards such as credit and promotional cards, has low energy consumption, low cost and high embossing accuracy. The Model 1803 is described in detail in application Ser. No. 820,705. The Model 1803 does not have a magnetic recording station for recording one or more tracks of digitally encoded characters on the magnetic recording medium typically found on a conventional credit card. Embossing systems for making credit cards which include a magnetic recording system are more versatile than the Model 1803 for the reason that they can be used for both the making of promotional cards, which do not have a magnetic recording medium and credit cards. Currently hundreds of millions of credit cards and promotional cards are made each year.
An important feature of the Model 1803 is the use of single card transport mechanism to move cards between successive in line embossing units for embossing multiple lines of alphanumeric characters with one line being embossed with OCR characters of one pitch and two lines of alphanumeric characters of a second pitch. While the card transport mechanism has proved satisfactory in operation, its cost of manufacture has been relatively high because of the use of multiple rolling supports for each of a plurality of card gripping units and cams for activating and deactivating the card gripping functions of the card gripping units.
The Model 1803 transport mechanism establishes a horizontal reference position of the individual cards with respect to the individual embossing units by a pin which extends orthogonal to the direction of travel of a belt carrying the card gripping units from the rear portion of a trailing card gripping unit attached to the belt. This mechanism, while being adequate for a system for embossing promotional cards which do not have precise tolerances for the beginning and ending of embossed and magnetically recorded digitally encoded tracks of characters is inadequate to establish requisite positional tolerances for embossed lines of characters and magnetically recorded tracks in credit cards. The manufacturing operation of the belt in the Model 1803 does not permit the accurate location of the card gripping unit to a center to center spacing of adjacent pins that is necessary to meet embossed and magnetically recorded track locations for credit cards.
The stacker for the Model 1803, which collects the completed embossed cards, has a surface for receiving the embossed cards in the same horizontal plane as the transport path of the embossed cards through a topping station. This system has the disadvantage that the frictional forces between adjacent embossed cards can be so high to interfere with the individual cards being properly discharged from the topper transport unit into their proper position on the surface in the stacker.
Certain credit cards, such as AMERICAN EXPRESS, have the account number characters indented on the back surface by the joint action of a male punch which penetrates the back surface without appreciably deforming the front surface and an anvil which impacts the front surface to provide support. A ribbon is used to apply highlighting to the indented characters to make them visible. This embossing is known as "indent printing".
Commercial embossing systems for making credit cards have one or more pairs of embossing wheels for embossing separate lines of 7 and 10 pitch characters including the customer's name, account, expiration date and organization affiliation in 10 pitch alphanumeric characters, the customer's account in 7 pitch OCR characters and indent printing of the account number in 10 pitch characters. These systems activate both the male and female character forming elements by a pair of movable elements such as pivotable arms. The embossing wheels are positioned, by one or more shaft encoders, in the imprinting position for the desired 7 or 10 pitch character or the desired indent character to be printed. The one or more embossing wheels require complementary sets of parts for the activation of both the male punch and anvil for indent printing which complicates the structure and increases the cost to perform indent embossing. The Model 1803 embossing system manufactured by the assignee of the present invention does not perform indent printing.
U.S. Pat. Nos. 4,180,338 and 4,378,733 disclose embossing systems with character sets being carried by a pair of wheels.
The Model 15000 embossing system manufactured by Data Card Corporation has a separate station for performing indent printing. The specification of the vertical location of the indent printing line on a credit card prevents the use of a common support shaft for the pair of wheels respectively carrying the male and female embossing elements. The vertical location of the line of indent printing is so close to the top of the card that the bottom edge of the card interferes with the axis of rotation of the pair of wheels to prevent passage between the wheels. The Model 15000 uses a pair of embossing wheels which are respectively driven by separate shaft encoders that respectively carry a male indent embossing element and a movable anvil. Because a common shaft could not be used, it was necessary to use a second expensive shaft encoder for each of the individual wheels of the indent printer in order to maintain proper position of the characters for embossing.
Embossing systems which use a single pair of wheels to emboss all characters, including indent type characters, cannot use a common support shaft to bear the high forces present in embossing the non-indent characters. Without a common support shaft, it is necessary to employ massive support structures to bear the high forces present during embossing non-indent type characters. The Data Card Model 15000 uses this type of design.
In the credit card industry it is essential that the digitally encoded magnetically recorded tracks of characters must be recorded with total accuracy without dropouts being present. Verification systems for determining the accuracy of recording the tracks of digitally encoded data on a magnetic recording medium of a credit card in embossing systems are known. A first type of system uses a recording head which records digital data on the magnetic recording medium of a credit card and a separate playback head physically displaced from the recording head. With this system the previously recorded magnetic recording medium of the credit card is played back by the playback head for verification of the accuracy of the recording process. The data card Model 1500 and 15000 embossing systems uses the aforementioned verification system. The played back data is compared with stored data which was desired to be recorded to complete the verification process. A second type of system is exemplified by that disclosed in U.S. Pat. No. 4,518,853 which has been utilized in the Data Card Corporation Model 300 embossing system. This system uses a single fixed magnetic head which records the digital data on the recording medium on the first pass of the card past the head and verifies the accuracy of the recording with a second pass of the card past the head in the same direction as recording with the played back data being compared with the stored source of the data which was desired to be recorded.
Both of the aforementioned systems have disadvantages. The first system requires additional space for the separated heads which adds to the expense of the system and affects throughput. The second system has the disadvantage of requiring four passes of the card past the record head to complete the recording and verification process which also affects throughput.
Verification systems for recorded data are also known outside the credit card industry which use two physically separated magnetic heads which are moved in unison to perform the recording and verification process of encoded digital data. The first head records the digital data. The second head reads the data which has previously been recorded. The data which is read by the second head is compared with data stored in memory which was the source of the data to be recorded. The aforementioned technique of verification of the accuracy of the recording of data using two heads would have disadvantages in an embossing and encoding system for credit cards wherein individual cards are sequentially processed. In the first place, in order to read and write with two heads while processing the same card requires the adjacent heads to be magnetically shielded from each other to avoid cross-coupling that could introduce error into the verification process. Second, the physical separation of record and playback heads to respectively record and playback from the same card or adjacent cards would increase the length of the transport system from the source of the blank cards to the topping station which could affect throughput. In the situation where the heads would record and play back from adjacent cards, the transport system path length would be elongated by more than a card length.
U.S. Pat. No. 3,579,211 discloses a system for verifying the accuracy of the recording process of single multibit characters on a magnetic tape which reverses the direction of tape motion for the playback of a recorded character. A single magnetic head records a single digitally encoded character by movement of the tape in a first direction and plays back the single recorded character for verification of the accuracy of the recording process by movement of the tape in a second direction opposite to the first direction. This patent is directed to verification of the accuracy of the recording of a single multibit character at a time and does not disclose the use of a check character in the process of verification of a string of digitally encoded multiple characters of digital data stream by playback of the recorded data with movement of the magnetic recording medium in the opposite direction.
Prior to description of the present invention, it is important to understand the layout of the front and back sides of a conventional credit card such as, but not limited to, AMERICAN EXPRESS. Credit cards have up to four lines of embossed alphanumeric characters comprised of an OCR 7 pitch account number and two or three lines of 10 pitch alphanumeric characters identifying the customer name, expiration date and optionally the customer's group affiliation and one line of 10 pitch indent printing which typically is located on the back surface.
FIG. 1a illustrates the front surface of a typical credit card 10 of the above-referenced type which is embossed with the present invention. As illustrated, the card 10 has a format of a conventional credit card. The line 14 is the account number which is embossed with numeric characters of 7 pitch with center to center spacing of 1/7 of an inch. Two additional lines 16 are embossed with alphanumeric lines of characters of 10 pitch with a center to center spacing of 1/10 of an inch. These lines typically identify the expiration date of the card and the customer's name. One additional line 18, which identifies the customer's affiliation, may be embossed. The legend at the bottom of the card is marked in units of distance that the transport unit for the cards moves during the embossing of 7 and 10 pitch characters in the Model 1803 described above and in the present invention. The "0" position represents the left-hand margin which is specified by industry specification and the "180" represents the right-hand margin which is also specified by industry specification. The movement of the card transport unit in terms of the basic unit of distance is described below.
FIG. 1b illustrates the back surface 20 of the credit card of the above-referenced type which is printed with indent characters of the account number and magnetically recorded with three tracks of digitally encoded characters. The three tracks are contained on a magnetic recording medium 22. The layout of the three tracks is described below in conjunction with FIG. 2. The indent printing 24 is formed by a male printing element which forces a ribbon bearing a black plastic coating into the surface of the back surface 20 to produce a blackened indented print of the account number. The front surface 12 of the card is not appreciably deformed as a consequence of the front of the card being forced into surface contact with a fixed anvil as the indent character male element impacts the corresponding area on the back surface.
FIG. 2 illustrates a breakdown of the information content of the tracks 1, 2 and 3 of digitally encoded characters which may be present on a credit card. The information to the right of the track identification number respectively states the recording density in bits per inch, the number of bits per character and the maximum character number of each of the tracks. The tracks 1, 2 and 3 are recorded with the above-referenced configuration in accordance with the industry standard discussed below in FIGS. 3-5. Track 1 was developed by the International Air Transport Association (IATA). Track 2 was developed by the American Bankers Association (ABA). Track 3 was developed by the thrift industry. Fewer characters than the maximum number illustrated in FIG. 2 are typically used with the track length of encoded characters being proportional to the number of characters.
FIG. 3 illustrates a detailed breakdown of the information content of track 1 described above with reference to FIG. 2. Track 1 begins with a start sentinel SS which is encoded as a % character, followed by a format code FC, followed by a field separator or FS which is encoded by a left parenthesis character, followed by the card holder's name, followed by another field separator, followed by additional data, followed by an end sentinel ES, which is encoded by a question mark character, and concluding with longitudinal redundancy check character LRC. The longitudinal redundancy check character LRC is formed by the sequential calculation of EXCLUSIVE OR function of each of the bits of the 78 characters preceding the LRC. The LRC is calculated by the corresponding encoding bits of the first and second characters being exclusively ORed together, followed by the third character being exclusively ORed with the resultant of the previous EXCLUSIVE OR function, etc. until all of the characters have been processed by the EXCLUSIVE OR logic function. The LRC is a type of "check character" which is a unique function of the encoded characters which precede the LRC. The LRC character is an industry specification for verification of the accuracy of the recording process.
FIG. 4 illustrates a detailed breakdown of the information content of track 2 described above with reference to FIG. 2. The track 2 contains SS, PAN, FS, Additional Data, ES and LRC fields of the same general purpose described above with reference to FIG. 3. Track 2 omits the FC field found in track 1 described below. The LRC is calculated in a manner analogous to the LRC of track 1 described above.
FIG. 5 illustrates a detailed breakdown of the information content of track 3 described above with reference to FIG. 2. The LRC is calculated in a manner analogous to the LRC of FIG. 1.
The recording of each of the tracks begins with the start sentinel SS and ends with the LRC. Industry standards specify that the centerline of the first data bit of the SS for each track is located 0.293.+-.0.20 inches from the right-hand margin and the centerline of the last bit of the LRC is located no closer to the left-hand edge than 0.273 inches.
The encoding technique for each track is a two frequency coherent phase recording in which the data is comprised of data bits and clocking bits together in one signal. An intermediate flux transition occurring between clocking transitions signifies a high level (one) and the absence of an intermediate flux transition signifies a low level (zero). The data for each track from the SS to the LRC is recorded as a continuous sequence of encoded multibit characters without intervening gaps. The encoding technique is described in detail on pages 8-10 of the Aug. 30, 1975 publication of the American National Standards Institute, Inc. entitled American National Standard Magnetic-Stripe Encoding for Credit Cards.
The portion of the magnetic recording medium which precedes the first bit of the start sentinels SS of each track 1, 2 and 3 and the portion of the magnetic recording medium which follows the last bit of the longitudinal redundancy check character LRC is recorded with successive binary zeros. The first bit of the SS is always chosen as a "1" to mark the beginning of each track.